Thermodynamic study on co-deposition of ZrB2–SiC from ZrCl4–BCl3–CH3SiCl3–H2–Ar system

Abstract Thermodynamics phase diagram of ZrB 2 –SiC co-deposited from precursors of ZrCl 4 –BCl 3 –CH 3 SiCl 3 (methyltrichlorosilane, MTS)–H 2 –Ar has been investigated in detail by using the FactSage code and its embedded database (130 species being involved). The yields of condensed phases in the co-deposition process have been examined as the functions of the inject reactant ratios of BCl 3  / (BCl 3  + MTS) and H 2  / (ZrCl 4  + BCl 3  + MTS), and the temperature at a fixed pressure of 5 kPa. The results show that their yields strongly depend on the molar ratios of the inject reactants and the temperature. Consequently, the pure ZrB 2 –SiC composite without free C, B 4 C, ZrC and ZrSi can be co-deposited under the ideal condition by adjusting the reactant ratios and the temperature. The gas-phase equilibrium concentration distribution shows that the high input amount of H 2 is favorable for the co-deposition of ZrB 2 and SiC at a fixed ratio of ZrCl 4 :BCl 3 :MTS:Ar. In the end, the theoretical results can lay down guidelines for increasing the experimental yields of ZrB 2 and SiC.